HaikuDepot: Don't try to send "unspecified" stability

Set to empty string and cause the JSON to have null. Fixes sending/editing
comments without specifying a stability rating.

src/apps/haikudepot/model/WebAppInterface.cpp

@@ -471,7 +471,7 @@ WebAppInterface::CreateUserRating(const BString& packageName,
 				.AddValue("pkgVersionType", "LATEST")
 				.AddValue("userNickname", fUsername)
 				.AddValue("rating", rating)
-				.AddValue("userRatingStabilityCode", stability)
+				.AddValue("userRatingStabilityCode", stability, true)
 				.AddValue("comment", comment)
 				.AddValue("naturalLanguageCode", languageCode)
 			.EndObject()
@@ -496,7 +496,7 @@ WebAppInterface::UpdateUserRating(const BString& ratingID,
 			.AddObject()
 				.AddValue("code", ratingID)
 				.AddValue("rating", rating)
-				.AddValue("userRatingStabilityCode", stability)
+				.AddValue("userRatingStabilityCode", stability, true)
 				.AddValue("comment", comment)
 				.AddValue("naturalLanguageCode", languageCode)
 				.AddValue("active", active)

src/apps/haikudepot/ui/RatePackageWindow.cpp

@@ -427,7 +427,7 @@ RatePackageWindow::_QueryRatingThread()
 		}
 		if (result.FindString("userRatingStabilityCode",
 			&fStability) == B_OK) {
-			int32 index = -1;
+			int32 index = 0;
 			for (int32 i = fStabilityCodes.CountItems() - 1; i >= 0; i--) {
 				const StabilityRating& stability
 					= fStabilityCodes.ItemAtFast(i);
@@ -493,6 +493,9 @@ RatePackageWindow::_SendRatingThread()
 
 	Unlock();
 
+	if (stability == "unspecified")
+		stability = "";
+
 	status_t status;
 	BMessage info;
 	if (ratingID.Length() > 0) {